U.S. patent application number 10/636784 was filed with the patent office on 2004-03-04 for heterogeneous gaseous chemical reactor catalyst.
Invention is credited to Combs, Glenn A..
Application Number | 20040043900 10/636784 |
Document ID | / |
Family ID | 31720607 |
Filed Date | 2004-03-04 |
United States Patent
Application |
20040043900 |
Kind Code |
A1 |
Combs, Glenn A. |
March 4, 2004 |
Heterogeneous gaseous chemical reactor catalyst
Abstract
An improved heterogeneous catalyst for catalyzing the reaction
of gaseous reactants, comprising a high performance catalyst
particle with a diameter to height ratio in the range between about
0.5:1 to 1.0:1.0, the high performance catalyst particle has a
Relative Particle Size Parameter (RPSP) and a Geometric Surface
Area (GSA), wherein the high performance catalyst particle has a
higher GSA for a particular RPSP than a prior art catalyst
particle. In another embodiment the improved heterogeneous catalyst
with a diameter to height ratio in the range between about 0.5:1 to
1.0:1.0 has a Relative Particle Size Parameter (RPSP), a Geometric
Surface Area (GSA), and an associated Relative Pressure Drop (RPD),
wherein the high performance catalyst particle has a higher GSA for
a particular RPSP or alternately a lower RPD for a particular GSA
than a prior art catalyst particle.
Inventors: |
Combs, Glenn A.; (Monroe,
LA) |
Correspondence
Address: |
Richard C. Litman
LITMAN LAW OFFICES, LTD.
P.O. Box 15035
Arlington
VA
22215
US
|
Family ID: |
31720607 |
Appl. No.: |
10/636784 |
Filed: |
August 8, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60402580 |
Aug 12, 2002 |
|
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Current U.S.
Class: |
502/439 ;
502/527.19; 502/527.24 |
Current CPC
Class: |
C01B 2203/1011 20130101;
C01B 2203/1247 20130101; B01J 35/026 20130101; C01B 2203/0844
20130101; B01J 23/78 20130101; C01B 2203/1052 20130101; C01B
2203/142 20130101; C01B 2203/82 20130101; B01J 23/755 20130101;
C01B 2203/0233 20130101; B01J 2219/32279 20130101; C01B 2203/1005
20130101; B01J 23/83 20130101; C01B 3/40 20130101; C01B 2203/0244
20130101; Y02P 20/52 20151101; C01B 2203/1047 20130101 |
Class at
Publication: |
502/439 ;
502/527.19; 502/527.24 |
International
Class: |
B01J 035/04 |
Claims
I claim:
1. An improved heterogeneous catalyst for catalyzing the reaction
of gaseous reactants, comprising a high performance catalyst
particle with a diameter to height ratio in the range between about
0.5:1 to 1.0:1.0, the high performance catalyst particle has a
Relative Particle Size Parameter (RPSP) and a Geometric Surface
Area (GSA), wherein the high performance catalyst particle has a
higher GSA for a particular RPSP than a prior art catalyst
particle.
2. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial pear-shaped hole.
3. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial elliptical hole.
4. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial L-shaped hole.
5. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial rounded diamond-shaped hole.
6. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial diamond-shaped hole.
7. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one axial internal slot-hole.
8. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial pear-shaped hole and at least one external slot
hole.
9. The improved heterogeneous catalyst according to claim 1,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial teardrop hole.
10. The improved heterogeneous catalyst according to claim 1
further comprising, alone or in combination, the elements or oxides
of the elements Nickel, Cobalt, Lanthanum, Platinum, Palladium,
Iridium, Rhodium, Rhenium, Ruthenium, Tin, Lead, Antimony, Bismuth,
Germanium, and Arsenic.
11. The improved heterogeneous catalyst according to claim 1
further comprising, alone or in combination, Potash or other
Alkali-Compounds, Zirconium or Magnesium oxides, alpha-Alumina,
Calcium-Aluminate, Magnesia-Alumina, Zirconia, and Spinel.
12. An improved heterogeneous catalyst for catalyzing the reaction
of gaseous reactants, comprising a high performance catalyst
particle with a diameter to height ratio in the range between about
0.5:1 to 1.0:1.0, the high performance catalyst particle has a
Relative Particle Size Parameter (RPSP), a Geometric Surface Area
(GSA), and an associated Relative Pressure Drop (RPD), wherein the
high performance catalyst particle has a higher GSA for a
particular RPSP or alternately a lower RPD for a particular GSA
than a prior art catalyst particle.
13. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial pear-shaped hole.
14. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial elliptical-shaped hole.
15. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial L-shaped hole.
16. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial rounded diamond-shaped hole.
17. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial diamond-shaped hole.
18. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial slot-shaped hole.
19. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial pear-shaped hole and at least one external
slot-shaped hole.
20. The improved heterogeneous catalyst according to claim 12,
wherein the heterogeneous catalyst particle is a cylindrical ring
catalyst, wherein the cylindrical ring catalyst defines at least
one internal axial teardrop-shaped hole.
21. The improved heterogeneous catalyst according to claim 12,
wherein the high performance catalyst particle is comprised, alone
or in combination, of the elements or compounds of the elements
Nickel, Cobalt, Lanthanum, Platinum, Palladium, Iridium, Rhodium,
Rhenium, Ruthenium, Cerium, Cesium, Yttrium, Molybdenum, Copper,
Zinc, Manganese, Chromium, Calcium, Titanium, Iron, Zirconium,
Magnesium, Phosphorus, Potassium, Tin, Lead, Antimony, Bismuth,
Germanium, Arsenic and compounds Alumina, alpha-Alumina,
Calcium-Aluminate, Magnesia-Alumina, Zirconia, Spinel, Thoria,
Titania, Silica, Beryllia, Potash or other Alkali-Compounds.
22. A cylindrical catalyst for catalyzing the reaction of gaseous
reactants, wherein the cylindrical catalyst defines at least one
axial hole with circular curves combined with straight edges to
form closed elongated curved shapes which possess greater hole
peripheral circumference than holes of circular or regular-polygon
shapes of the prior art.
23. The improved heterogeneous catalyst according to claim 22,
wherein the high performance catalyst particle is comprised, alone
or in combination, of the elements or compounds of the elements
Nickel, Cobalt, Lanthanum, Platinum, Palladium, Iridium, Rhodium,
Rhenium, Ruthenium, Cerium, Cesium, Yttrium, Molybdenum, Copper,
Zinc, Manganese, Chromium, Calcium, Titanium, Iron, Zirconium,
Magnesium, Phosphorus, Potassium, Tin, Lead, Antimony, Bismuth,
Germanium, Arsenic and compounds Alumina, alpha-Alumina,
Calcium-Aluminate, Magnesia-Alumina, Zirconia, Spinel, Thoria,
Titania, Silica, Beryllia, Potash or other Alkali-Compounds.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Serial No. 60/402,580, filed Aug. 12, 2002.
1. FIELD OF THE INVENTION
[0002] The present invention is directed to advanced catalyst
shapes that increase catalyst performance while reducing gas
pressure drop.
2. BACKGROUND OF THE INVENTION
[0003] Catalysts are employed in chemical reactors to promote the
conversion of reactants to desired products. Good catalysts induce
rapid transformation of chemical molecules to combine into
different molecules while the catalyst itself is not expended or
altered.
[0004] A catalyst that exists in a different phase as the chemical
reactants is called a heterogeneous catalyst such as a solid
catalyst used to transform gaseous reactant molecules to a useful
gaseous product such as hydrogen. A heterogeneous catalyst system
comprises a plurality of heterogeneous catalyst particles. Each
heterogeneous catalyst particle typically comprises internal voids
such as holes that travel the length of the particles to define
apertures at both ends of the catalyst particle; external voids
also form between catalyst particles when the particles are packed
into, for example, a hollow tube. The gaseous reactants flow
through the voids. Inefficient fluid flow can result in undesirable
fluid friction losses. Heterogeneous catalyst research is focused
on minimizing fluid friction losses while maximizing the conversion
of gaseous reactants into desired reaction products.
[0005] "Hydrocarbon Reforming" is a term used to describe the
process by which a heterogeneous catalyst converts hydrocarbons
into hydrogen (and carbon monoxide). The generated hydrogen is
used, for example, in the industrial manufacture of ammonia and
methanol. In Hydrocarbon Reforming processes, hydrocarbons such as
methane, and/or heavier hydrocarbon molecules, are combined with
steam or carbon dioxide and reacted across a plurality of
heterogeneous catalyst particles. The heterogeneous catalyst
particles are typically packed inside the hollow bores of heated
tubes or within pressure vessels, operating at 900-2400 degrees
Fahrenheit and pressures from about 10 to 50 atmospheres.
[0006] Competing simultaneous Hydrocarbon Reforming and
Water-Gas-Shift reactions occur on the active sites of the
catalyst, as follows:
[0007] Steam-Hydrocarbon Reforming Reactions:
CH.sub.4+H.sub.2O=CO+3H.sub.2 (+49.2 kcal/mole)
C.sub.2H.sub.6+2H.sub.2O=2CO+5H.sub.2
C.sub.3H.sub.8+3H.sub.2O=3CO+7H.sub.2 . . . and similarly for
higher hydrocarbon reactants.
[0008] For Hydrogen Production by Reaction with CO.sub.2:
CH.sub.4+CO.sub.2=2CO+2H.sub.2
C.sub.2H.sub.6+2CO.sub.2=4CO+3H.sub.2
C.sub.3H.sub.8+3CO.sub.2=6CO+4H.sub.2 . . . and similarly for
higher hydrocarbon reactants.
[0009] Water-Gas-Shift Reaction:
CO+H.sub.2O=CO.sub.2+H.sub.2 (-9.84 kcal/mole)
[0010] Steam-Hydrocarbon and Carbon Dioxide-Hydrocarbon Reforming
reactions are highly endothermic (i.e., require input of energy)
and hydrogen production is best achieved by external heating of the
gaseous reactant mixture in the presence of heterogeneous catalyst
particles.
[0011] The Water-Gas-Shift reaction is exothermic (i.e., releases
energy in the form of heat energy). Hydrocarbons heavier than
methane are cracked catalytically to olefins and methane and then
react further with steam yielding a gaseous product comprising a
mixture of gases such as hydrogen, carbon monoxide, carbon dioxide
and inert gases (e.g., nitrogen, helium and argon that are normally
present in natural gas).
[0012] The chemical kinetics of the hydrocarbon reforming reaction
is strongly influenced by the amount of catalytic surface area
(referred to as geometric surface area (GSA) available to reactants
on the heterogeneous catalyst particle. Specifically, the catalysis
rate is limited by the diffusion rate of the gaseous reagents in
the catalyst elements (see U.S. Pat. No. 4,089,941 issued May 16,
1978 to B. Villemin, column 1, and lines 49-60). Efforts have
concentrated on increasing the contact area between the gaseous
reagents and the catalyst. Decreasing the size of the catalyst
elements increases the geometric surface area (GSA) of the
catalyst. However, increasing the GSA can lead to a pressure drop
penalty that deleteriously affects the synthesis of hydrogen (and
carbon monoxide).
[0013] In auto-thermal reforming high temperature air or oxygen
enriched air can be added to gas mixtures containing the reaction
products from previous hydrocarbon reforming catalytic steps to
produce higher levels of hydrogen and lower concentrations of
hydrocarbon reactants such as methane. Auto-thermal reforming
maximizes conversion of reactant hydrocarbons into desired hydrogen
and carbon monoxide-carbon dioxide reaction products.
[0014] A key indicator of reforming catalyst performance is the
extent of conversion of methane into hydrogen product, or the
methane content in catalyst exit gases ("methane leakage") for
specific reactor temperature, pressure and gas throughput.
Increasing the operating temperature reduces the amount of methane
content in the exit gases.
[0015] In practical operation, the methane content in the exit gas
from reforming catalyst is greater than the theoretical equilibrium
value at a given temperature such that there is a lower equilibrium
temperature where the observed higher methane composition would
exist at equilibrium. This difference in temperature is commonly
referred to as the Methane Approach to equilibrium.
[0016] Catalyst size and shape also impact on reformer gas pressure
losses and catalyst strength, which likewise influences practical
useful catalyst life. For externally fired tubular arrangements of
hydrocarbon reforming reactor equipment, catalyst activity is a
direct indication of catalyst tube metal temperature at times
throughout the life of a catalyst charge, apart from other
influences of plant throughput and specific reformer operating
conditions. In normal service as reforming catalyst ages, tube
metal temperature increases for otherwise fixed operating
conditions, due to the loss of available catalytic component
surface area from thermal sintering of active catalytic component
crystallites to gradual larger size. Thus catalyst tube metal
temperature is a direct indicator of catalyst activity throughout
catalyst life for tubular hydrocarbon reforming reactors.
[0017] A review of the prior art follows.
[0018] U.S. Pat. No. 2,408,164 issued Sep. 24, 1946 to A. L.
Foster, describes the preparation of catalytic materials suitable
for pressing into various catalyst shapes.
[0019] U.S. Pat. No. 4,089,941 issued May 16, 1978 to B. Villemin,
describes an impregnated nickel catalyst for the steam reforming of
gaseous hydrocarbons to produce hydrogen, comprising a support
containing at least 98% of alumina, having the shape of a cylinder
containing at least four partitions located in radial planes and in
which the porosity ranges between 0.08 and 0.20 cm.sup.3/g, and 4
to 15% of nickel calculated as nickel oxide (NiO) with respect to
the total weight of the catalyst, deposited by impregnation on the
support.
[0020] U.S. Pat. No. 4,233,187 issued Nov. 11, 1980 to Atwood, et
al., describes a catalyst for use in the steam-hydrocarbon
reforming reaction. The '187 catalyst comprises a group VIII metal
on a cylindrical ceramic support consisting essentially of alpha
alumina and having a plurality of gas passages extending axially
there through.
[0021] U.S. Pat. No. 4,328,130 issued May 4, 1982 to C. P. Kyan,
describes a shaped catalyst. The '130 catalyst has substantially
the shape of a cylinder having a plurality of longitudinal channels
extending radially from the circumference of the cylinder defining
protrusions there-between. The protrusions have a maximum width
greater than the maximum width of the channels.
[0022] U.S. Pat. No. 4,337,178 issued Jun. 29, 1982 to Atwood, et
al., describes a catalyst that comprises a normally cylindrical
refractory support having gas passages communicating from end to
end and oriented parallel to its axis and having gas passages in
the shape of segments of circles (pie-shaped), square, hexagonal,
circular, oval or sinusoidal. The exterior and interior surfaces of
the '178 catalyst are coated with catalytic compositions. The
length of the refractory support is significantly less than the
diameter. A ratio of height to effective internal diameter (H:ID)
of less than 4:1 for each gas passage provided greater catalytic
effectiveness than H:ID ratios greater than 4. One difficulty with
this catalyst shape is that it cannot be produced in small
diameters as rings where the diameter to height ratio is
substantially less than 1.5:1 to achieve higher geometric surface
area or to lower pressure drop because the hole sizes become too
small, rendering the catalyst difficult to manufacture.
[0023] U.S. Pat. No. 4,441,990 issued Apr. 10, 1984 to Yun-Yang
Huang, describes various cross-section shapes applied to a
catalytic particle. Examples of cross-section shapes are
rectangular shaped tubes, and triangular shaped tubes. The catalyst
particle has a non-cylindrical centrally located aperture
surrounded by a solid wall portion, a volume to surface ratio of
less than about 0.02 inch and an external periphery characterized
by having at least three points of contact when circumscribed by a
cylindrical shape. The '990 catalyst particles comprise of shapes
with smaller geometric surface area than multi-holed axial
cylindrical ring catalyst shapes of comparable catalyst size with a
concomitant deleterious impact on catalyst activity.
[0024] U.S. Pat. No. 5,527,631 issued Jun. 18, 1996 to Singh et
al., describes a catalyst support that defines at least one
discrete passageway extending along the length of the non-rigid,
porous, fibrous catalyst support forming a reformable gas flow
channel in heat communication with means for heating the reformable
hydrocarbon gas, wherein the catalyst impregnated on the catalyst
support comprises Ni and MgO. Such a non-rigid, porous, fibrous
catalyst would be difficult to produce in commercial quantities
because of the small size and characteristic shape of the interior
discrete flow channels.
[0025] None of the above inventions and patents, taken either
singly or in combination, is seen to describe the instant invention
as claimed. Thus, a catalyst and method of making thereof solving
the aforementioned problems is desired.
SUMMARY OF THE INVENTION
[0026] An improved heterogeneous catalyst for catalyzing the
reaction of gaseous reactants, comprising a high performance
catalyst particle with a diameter to height ratio in the range
between about 0.5:1 to 1.0:1.0, the high performance catalyst
particle has a Relative Particle Size Parameter (RPSP) and a
Geometric Surface Area (GSA), wherein the high performance catalyst
particle has a higher GSA for a particular RPSP than a prior art
catalyst particle.
[0027] In another embodiment the improved heterogeneous catalyst
with a diameter to height ratio in the range between about 0.5:1 to
1.0:1.0 has a Relative Particle Size Parameter (RPSP), a Geometric
Surface Area (GSA), and an associated Relative Pressure Drop (RPD),
wherein the high performance catalyst particle has a higher GSA for
a particular RPSP or alternately a lower RPD for a particular GSA
than a prior art catalyst particle.
[0028] In a further embodiment a cylindrical catalyst defines at
least one axial hole with greater hole peripheral circumference
than holes of circular or regular-polygon shapes of the prior
art.
[0029] Accordingly, it is a principal object of the invention to
provide an improved catalyst particle for catalyzing the reaction
of gaseous reactants.
[0030] It is another object of the invention to provide an improved
catalyst particle for catalyzing Hydrocarbon Reforming
reactions.
[0031] It is a further object of the invention to provide a
cylindrical catalyst for catalyzing the reaction of gaseous
reactants.
[0032] It is an object of the invention to provide improved
elements and arrangements thereof for the purposes described which
is inexpensive, dependable and fully effective in accomplishing its
intended purposes.
[0033] These and other objects of the present invention will become
readily apparent upon further review of the following specification
and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 shows a perspective view of a segment of chemical
reaction tube filled with a plurality of improved catalyst
particles of the present invention.
[0035] FIG. 2 shows a cut-away view of the segment of chemical
reaction tube of FIG. 1.
[0036] FIG. 3 shows separate perspective, top and bottom, and
elevation views of a range of heterogeneous ring catalysts of the
prior art.
[0037] FIG. 4 shows the relationship between Relative Pressure Drop
and Relative Particle Size calculated for the prior art Catalysts A
to E.
[0038] FIG. 5 is a graph of geometric surface area (GSA) verses the
Relative Particle Size Parameter (RPSP) calculated for the prior
art Catalysts A to E.
[0039] FIG. 6 is a graph of GSA verses RPSP for Raschig Ring
catalyst shapes.
[0040] FIG. 6A shows a catalyst pressure-drop measuring
apparatus.
[0041] FIG. 7 shows separate perspective, top and bottom, and
elevation views of cylindrical catalysts with at least one internal
pear-shaped hole according to the present invention.
[0042] FIG. 8 shows a graph of GSA v. RPSP of a cylindrical ring
catalyst with five internal generally pear shaped holes according
to the present invention.
[0043] FIG. 9 shows separate perspective, top and bottom, and
elevation views of cylindrical catalysts with at least one internal
generally elliptical shaped hole according to the present
invention.
[0044] FIG. 10 shows a graph of GSA v. RPSP of a cylindrical ring
catalyst with six internal generally elliptical shaped holes
according to the present invention.
[0045] FIG. 11A shows separate perspective, top and bottom, and
elevation views of cylindrical catalysts with at least one internal
L-shaped hole according to the present invention.
[0046] FIG. 11B shows a detailed view of the internal L-shaped hole
of FIG. 11A according to the present invention.
[0047] FIG. 12 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst with four internal generally L-shaped holes.
[0048] FIG. 13A shows separate perspective, top and bottom, and
elevation views of cylindrical catalysts with at least one internal
generally rounded-diamond-shaped hole according to the present
invention.
[0049] FIG. 13B shows a top view of an internal
rounded-diamond-shaped hole of FIG. 13A according to the present
invention.
[0050] FIG. 14 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst with five internal generally rounded-diamond-shaped holes
according to the present invention.
[0051] FIG. 15 shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst with at least one internal
generally diamond-shaped hole according to the present
invention.
[0052] FIG. 16 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst with five internal generally diamond-shaped holes
according to the present invention.
[0053] FIG. 17A shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst with at least one internal
generally slot-shaped hole according to the present invention.
[0054] FIG. 17B shows an internal asymmetric slot shaped hole
according to the present invention.
[0055] FIG. 18 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst with six internal generally slot-shaped holes according to
the present invention.
[0056] FIG. 19 shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst with at least one internal
generally pear-shaped axial hole and at least one external slot
shaped hole according to the present invention.
[0057] FIG. 20 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst with four internal generally pear-shaped axial holes and
four external slot shaped holes according to the present
invention.
[0058] FIG. 21A shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst with at least one internal
generally teardrop-shaped axial hole according to the present
invention.
[0059] FIG. 21B shows a further top (or bottom) view of the
catalyst of FIG. 21A.
[0060] FIG. 22 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst with six generally teardrop-shaped holes according to the
present invention.
[0061] FIG. 23 shows a table that compares the predicted catalytic
performance of a Raschig ring prior art catalyst with the predicted
catalytic performance of a teardrop hole catalyst according to the
present invention.
[0062] FIG. 24 shows a table that compares the predicted catalytic
performance of a fluted ring prior art catalyst with the predicted
catalytic performance of a slot-shaped hole catalyst according to
the present invention.
[0063] FIG. 25 shows a table that compares the predicted catalytic
performance of a fluted ring prior art catalyst with the predicted
catalytic performance of a four axial internal pear shaped hole and
four external slot hole catalyst according to the present
invention.
[0064] FIG. 26 shows a table that compares the predicted catalytic
performance of a four-holed ring prior art catalyst with that of an
axial internal pear holed catalyst according to the present
invention.
[0065] FIG. 27 shows a table that compares the predicted catalytic
performance of a four holed ring prior art catalyst with the
predicted catalytic performance of an axial internal rounded
diamond holed catalyst according to the present invention.
[0066] FIG. 28 shows a table that compares the catalytic
performance of a seven-holed prior art ring catalyst with the
predicted catalytic performance of an axial internal eliptical
holed catalyst according to the present invention.
[0067] FIG. 29 shows a table that compares the catalytic
performance of a seven-holed ring prior art catalyst with the
predicted catalytic performance of an axial internal diamond holed
catalyst according to the present invention.
[0068] FIG. 30 shows a table that compares the catalytic
performance of a seven spoke ring prior art catalyst with the
predicted catalytic performance of an axial L-shaped hole catalyst
according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0069] The present invention is directed to advanced catalyst
shapes that increase catalyst performance while reducing gas
pressure drop.
[0070] Referring to FIGS. 1 and 2, a segment of reaction tube 200
is shown filled with a plurality of improved catalyst particles 220
of the present invention. Reactants in gaseous form travel along
the inside of the reaction tube 200 and undergo chemical conversion
to desired gaseous reaction products, such as hydrogen, upon
contact with the surfaces presented by the catalyst particles 220
according to the invention.
[0071] FIG. 3 shows separate perspective, top and bottom, and
elevation views of a range of heterogeneous ring catalysts of the
prior art, i.e., the Raschig 240, Fluted 260, 4-Hole 280, 7-Hole
300, 7-spoke 320, and 10-Hole 340 rings. The rings 240, 260, 280,
300, 320, and 340 are hereinafter also referred to as Catalyst A
240, Catalyst B 260, Catalyst C 280, Catalyst D 300, Catalyst E
320, and Catalyst F 340, respectively. Catalysts A to E are
regarded as representative of the prior art.
[0072] Reference is made herein, for illustrative purposes only, to
the prior art Raschig ring 240 and 10-Hole ring 340 (i.e., Catalyst
A 240 and Catalyst F 340, respectively). Catalyst A 240 defines a
hole 360 that passes completely through Catalyst A 240 to define an
essentially identical aperture 380 in the top and bottom of
Catalyst A 240. Catalyst F 340 defines an outer ring of holes 400
and a central hole 420. The outer ring of holes 400 surround the
central hole 420. The holes 400 and 420 pass completely through the
Catalyst F 340 to respectively define apertures 440 and 460,
respectively, in the top and bottom of Catalyst F 340.
[0073] The theory of Relative Particle Size developed herein
asserts that for a given reactor tube of specific size and
operating temperature, with inlet pressure fixed along with unique
fluid flow rate and reactant composition, there exists only one
pressure drop for each unique catalyst "Relative Particle Size". If
the size of catalyst particles increase, regardless of the shape,
the pressure-drop of the gas will decrease due to increased void
fraction around fewer and larger catalyst particles in the tube.
Thus the theory of Relative Particle Size indicates that as
particles increase in size in a given tube flowing scenario, the
gas pressure losses decrease. Catalyst particles can "effectively
increase" in size through several means.
[0074] Increasing the overall external catalyst particle dimensions
(diameter, height or both) results in a greater loaded catalyst
void fraction resulting in lower gas pressure drop. Alternatively,
the combined internal area of a hole or holes within catalyst
particles may increase for otherwise fixed external catalyst
dimensions causing the same effect, higher void fraction and lower
gas pressure drop for gases passing through the catalyst. Thus, a
"Relative Particle Size" exists for all catalysts of any
proportions and shape, which combines all dimensional and shape
characteristics into a singular Relative Particle Size
Parameter.
[0075] FIG. 4 shows the relationship between Relative Pressure Drop
and Relative Particle Size calculated for the prior art Catalysts A
to E. Relative Pressure Drop is defined as the ratio of the fluid
pressure drop for one catalyst divided by the pressure drop of a
different catalyst for a given set of fluid flow conditions with
respect to the gaseous reactants flowing through the reaction tube
and the prior art catalyst therein.
[0076] The present invention is directed to exploiting a Relative
Particle Size Parameter (RPSP) for improving geometric surface area
(GSA) and decreasing pressure-drop. The Relative Particle Size
Parameter according to the invention takes account of the influence
of catalyst void fraction as it varies with catalyst dimensions,
number and size of interior holes in combination, along with
shape/size aspects of a catalyst configuration to explain pressure
drop. Relative Particle Size Parameter is defined as:
[0077] F.sub.h=Catalyst Void Fraction, including holes
[0078] Ds=Shape Parameter of a catalyst particle
[0079] RPSP=Relative Particle Size
Parameter=F.sub.h.sup.0.597*D.sub.s.sup- .1.0488422
[0080] where,
[0081] Ds, is a Catalyst Shape Parameter, defined as:
[0082] Ds=(6*V.sub.act/PI).sup.(1/3) (Inch Dimension)
[0083] where,
[0084] V.sub.act is the Volume of Actual Catalyst Mass in cubic
inches (excluding internal voidage)
[0085] PI=The Constant 3.1415926536
[0086] FIG. 5 is a graph of geometric surface area (GSA) verses the
Relative Particle Size Parameter (RPSP) calculated for the prior
art Catalysts A to E. Geometric surface area (GSA) is the available
external exposed catalyst surface, per unit of catalyst volume,
expressed as area/volume; for example Ft.sup.2/Ft.sup.3 (square
feet per cubic foot) or m.sup.2/m.sup.3 (square meters per cubic
meter). Each catalyst has a geometric surface area characteristic
and a corresponding Relative Particle Size Parameter (RPSP).
[0087] Raschig Ring catalyst shapes have the lowest geometric
surface area for varying Relative Particle Size Parameter.
Similarly, catalysts with small flutes on the periphery of the ring
have slightly higher GSA versus Relative Particle Size Parameter
than Raschig Rings. Still higher GSA for variation of Relative
Particle Size Parameter is achieved by catalyst shapes formed with
variations of multiple axial circular holes fashioned within the
ring. For example, Catalyst C and Catalyst D shapes have four or
seven axial circular inner holes and align on a common GSA versus
Relative Particle Size Parameter curve, with the difference between
these shapes principally in the number and size of axial circular
holes within the catalyst ring and their differing aspect ratio,
(diameter to height ratio).
[0088] FIG. 6 is a graph of GSA verses RPSP for Raschig Ring
catalyst shapes, and more particularly generalized GSA curves for
different catalyst void fractions. The distinctive dashed curves
shown on FIG. 6 illustrate 50, 55 and 60 percent void fractions for
GSA versus Relative Particle Size and characterize the most
important region for catalyst design and selections for catalysts
in hydrocarbon reforming reactors. The separate symbols for
individual dashed curves represent different diameter to height
ratios for Raschig Ring catalyst shapes.
[0089] It is apparent from FIG. 6 that higher performance (greater
GSA for given catalyst Relative Particle Size Parameter, "size"),
can be accomplished by control of at least two variables void
fraction or catalyst diameter/height ratio. Increasing void
fraction for a catalyst shape can increase geometric surface area
through increasing the size or number of holes within a catalyst
ring of given external proportions. This is generally accomplished
by increasing the number of internal holes while reducing internal
hole size to keep the loaded catalyst void fraction in an optimally
desirable range. The loaded catalyst void fraction is a critical
parameter, because it directly determines the gaseous reactants
velocity through and around catalyst particles, affecting
turbulence and residence time within the catalyst. Alternatively,
reducing catalyst diameter/height (length) ratio for a specific
loaded catalyst void fraction and Relative Particle Size Parameter
improves GSA and increases catalyst performance. In practice for
circular axial multi-holed cylindrical catalyst shapes this is
accomplished by reducing the number of holes through the catalyst,
while simultaneously making the ring smaller diameter and longer,
thereby maintaining a specific Relative Particle Size Parameter,
likewise maintaining a specific Relative Pressure Drop.
[0090] There is yet another characteristic, related to catalyst
shape that is not apparent from Raschig Ring catalyst shapes
represented in FIG. 6. Refer back to FIG. 5. Catalyst E has a
higher performance characteristic GSA versus Relative Particle Size
Parameter than any of the other axial multi-holed catalyst shapes
examined in this body of research. Refer to FIG. 3. Catalyst shape
E also has a very high diameter/height ratio, typically greater
than or about 2:1.
[0091] Small size Catalyst D (the axial 7 Hole Ring shape) has a
similar diameter/height ratio as Catalyst E, and both of these
shapes have nearly identical Relative Particle Size Parameter, (per
FIG. 5), yet catalyst E has considerably greater GSA. Based upon
GSA alone, Catalyst E is a higher performance, more efficient
catalyst shape than Small size Catalyst D. In this example
comparison, these two catalyst shapes have the same loaded catalyst
void fraction, (0.555) making GSA a true indication of overall
performance. As previously taught, it is possible for a particular
catalyst shape to have higher GSA by permitting greater internal
void fraction, (greater number of holes and hole area), resulting
in higher overall loaded catalyst void fraction. Increasing the
loaded catalyst void fraction is not necessarily desirable because
it can lead to turbulence problems affecting reactants heat
transfer, mixing and residence time in the catalyst.
[0092] The correlations of Relative Particle Size calculation of
the invention unexpectedly established that greater performing
catalysts are made from configurations of catalyst shapes that
define holes of particularly shapes that are axially aligned,
non-round shapes with uniform or non-uniform elongation of holes,
with holes optimally positioned entirely within the outer ring
diameter and favoring hole positioning in the region of the
circular ring toward the outside diameter or periphery of the
catalyst ring. This unexpected discovery explained why circular and
regular-polygon shaped holes, (triangular, square, etc.), are not
optimal shapes for optimizing catalyst performance.
[0093] FIG. 6A shows a catalyst pressure drop measuring apparatus
101 to measure gas (air) pressure drop in at least one test
catalyst 111 (e.g., cylindrical catalyst ring 480a in FIG. 7, see
below). The testing apparatus 101 comprises a 3 inch diameter
pressure tube 121 which contains the at least one catalyst 111; the
pressure tube 121 is preferably a schedule-40 carbon steel tube.
The pressure tube 121 has an inlet open end 131 and an exit open
end 141; the opposite ends 131 and 141 respectively define inlet
flange 161 and outlet flange 171, wherein flanges 161 and 171 are
preferably 3" (three inch) diameter 150 psi flanges. The inlet
flange 161 is welded to a 1" (one inch) inlet piping 181. The
outlet flange 171 is welded to a 11/2 inch schedule-40 outlet pipe
191 (the outlet pipe 191 comprises a gate valve 301); the outlet
flange 171 comprises a {fraction (3/16)} inches thick catalyst
support plate 187 that is sandwiched inside the outlet flange 171
as shown in FIG. 6A. The catalyst support plate 187 supports the at
least one catalyst 111. The catalyst support plate 187 comprises a
plurality of perforations 197 that permit airflow through the
pressure tube 121 (and by default the at least one catalyst 111).
The test apparatus 101 is designed to use a minimum quantity of
test catalyst 111 and to reach a reproducible pressure at the inlet
flange 161.
[0094] The flanges 161 and 171 comprise a series of holes to allow
pressure measurements directly at the inlet 131 and outlet 141 ends
of the pressure tube 121 using pressure measuring apparatus 201 and
211 to determine the pressure drop between the inlet 161 and outlet
flanges 171 for different test catalysts 111 to provide comparative
data for later analysis. The pressure measuring apparatus 201 and
211 comprise pressure gauges labeled "PI".
[0095] The inlet piping 181 is connected to an air compressor
system 221. The inlet piping 181 includes an inlet globe valve 231,
an armored rotor-meter 241 connected to an airflow meter 251
labeled "FI", an air temperature indicator 261 (labeled "TI" in
FIG. 6A), a gate valve 271, and a compressed air connector 281. The
connector 281 is attached to a pressure airline 291 and thence to
the air compressor system 221. The airflow meter 251 and air
temperature indicator 261 provide airflow and temperature data to
permit a person of ordinary skill in the art to normalize the
pressure data collected by the pressure measuring devices 201 and
211.
[0096] The testing apparatus 101 is run for about a minute to reach
equilibrium before pressure readings are taken at the inlet 161 and
outlet flanges 171. Therefore, both inlet and exit pressure can be
obtained in a very short time for a variety of induced pressures at
the inlet flange 161. A catalyst that exhibits a comparatively
lower pressure drop is representative of an improved catalyst.
EXAMPLE 1
[0097] FIG. 7 shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings 480 with at least one
internal pear-shaped hole 500 according to the present invention.
The rings 480a, 480b, 480c, 480d, and 480e define at least one
internal generally pear-shaped hole 500 that runs right through the
cylindrical ring 480 emerging at both ends of the ring 480. For
example, the cylindrical ring 480a defines three internal
pear-shaped holes 500a, 500b, and 500c; each of the holes 500a,
500b, and 500c run through the cylindrical catalyst 480a. It is
preferred that the axial pear-hole cylindrical ring 480 defines at
least three pear shaped holes 500. Each at least one pear shaped
hole 500 defines a first 520 and second 540 opposite ends of
overall semi-circular shape, wherein the first opposite end has a
diameter "d" and the second opposite end has a diameter "D2",
further wherein D2 is greater than d.
[0098] The first 520 and second 540 opposite ends define opposite
facing tapering sides 560 and 580. The catalyst 480 may optionally
defined curved or domed opposite ends 485a and 485b. The ends 485a
and 485b may be spherical, ellipsoidal or another curved shape, or
may be flat and circular. The dimensions d and D2 may be increased
or decreased depending on the number of holes 500 in the
cylindrical catalyst rings 480 (e.g., 480a). The advanced circular
cylindrical catalyst shape 480 has a preferred diameter to height
ratio in the range of 0.5:1 to 2.0:1, and more preferably in the
range of about 0.5:1 and 1.0:1.0.
[0099] Still referring to FIG. 7, with respect to catalyst strength
issues, dimensions "X1" and "X2" are shown. The dimensions X1 and
X2 represent the ligaments of catalyst material between the
circumference 600 and holes 500 of the catalyst particle 480. It
will be evident to a person of ordinary skill in the art that the
dimensions X1 and X2 are dependent on the other dimensions and the
number of generally pear shaped holes 500. For example, the
dimensions of the five holes 500a, 500b, 500c, 500d, and 500e can
be fixed as: D2=20% of D1, d=10% of D1, w=18.9% of D1, x1=8.4% of
D1, and x2=8.4% of D1.
[0100] FIG. 8 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 480c with five internal generally pear shaped holes 500.
The hatched area 620a indicates potential selections of the
cylindrical ring catalyst 480c with a diameter to height ratio in
the range between about 0.5:1 to 1.0:1.0. The high performance
catalyst particle 480c has a higher Relative Particle Size
Parameter (RPSP) and a Geometric Surface Area (GSA) for a
particular RPSP than Catalyst A through to Catalyst E.
EXAMPLE 2
[0101] FIG. 9 shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings 680, and more
specifically cylindrical catalyst rings 680a, 680b, 680c, and 680d
according to the invention. The cylindrical catalyst ring 680 may
optionally defined curved or domed opposite ends 685a and 685b. The
ends 685a and 685b may be spherical, ellipsoidal or another curved
shape, or may be flat and circular. The cylindrical catalyst rings
680a, 680b, 680c, and 680d define at least one internal generally
elliptical shaped hole 700 that runs right through the cylindrical
ring 680 to emerge at both ends of the ring 680. For example, the
cylindrical ring 680a defines four internal elliptical shaped holes
700a, 700b, 700c and 700d. It is preferred that the cylindrical
ring 680 defines at least three internal elliptical shaped holes
700. Each at least one internal elliptical shaped hole 700 has a
length 705 and a width 707. The dimensions 705 and 707 may be
increased or decreased depending on the number of internal holes
700 in the cylindrical catalyst rings 680 (e.g., 680a). The
advanced circular cylindrical catalyst shape 680 has a preferred
diameter to height ratio in the range of 0.5:1 to 2.0:1, and more
preferably in the range of about 0.5:1 and 1.0:1.0.
[0102] FIG. 10 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 680c with six internal generally elliptical shaped holes
700. The hatched area 620b indicates potential selections of the
cylindrical ring catalyst 680c with a diameter to height ratio in
the range between about 0.5:1 to 1.0:1.0. The high performance
catalyst particle 680c has a higher Relative Particle Size
Parameter (RPSP) and a Geometric Surface Area (GSA) for a
particular RPSP than a prior art catalyst particle.
EXAMPLE 3
[0103] FIG. 11A shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings 780, and more
specifically cylindrical catalyst rings 780a, 780b, and 780c
according to the present invention. The rings 780a, 780b, and 780c
define at least one generally L-shaped hole 800. For example, the
axial L-holed cylindrical ring 780c defines four L-shaped holes
800a, 800b, 800c and 800d. It is preferred that the axial L-hole
cylindrical ring 780 defines at least two L-shaped holes 800. Each
at least one L-shaped hole 800 has a length 705 and a width 707.
The catalyst 780 may optionally defined curved or domed opposite
ends 785a and 785b. The ends 785a and 785b may be spherical,
ellipsoidal or another curved shape, or may be flat and
circular.
[0104] With respect to FIG. 11B the L-shaped holes are formed of
circular or other curve shape hole ends 51' and 52', having widths
43' and 46'. Widths 43' and 46' are generally, but not necessarily
of equal length. FIG. 11B shows straight sides of L-shaped hole 800
as 55' and 55A' having lengths indicated as 44' and 45' and
straight sides of L-shaped hole 800 as 56' and 56A' having lengths
indicated as 57' and 58', further connected to inner and outer
curves 53' and 53A', combined with hole ends 51' and 52' to form
the characteristic L-shaped hole of this invention. Lengths 44' and
45' generally may be, but are not necessarily equal. Lengths 57'
and 58' generally may be, but are not necessarily equal. Inner and
outer curves 53' and 53A' may be of circular shape or another curve
shape. Dashed lines 59' in FIG. 11B indicate the positions where
curved ends 51', 52', inner and outer curves 53' and 53A', straight
sides 55' and 55A' and 56' and 56A' connect to form L-shaped hole
800.
[0105] Still referring to FIG. 11B, the L-shaped hole
characteristic dimensions 43', 44', 45', 46', 57' and 58' may be so
altered as desired along with the number of holes 800 to obtain an
optimal hole pattern within the interior of the catalyst shape 780
to achieve desired catalyst performance. The orientation of the
L-shaped holes 800 arrangement may vary, being parallel or
perpendicular to the radius from the central axis of the ring to
the outer diameter or in other arrangements, depending on the
number of L-shaped holes 800 selected, and catalyst strength or
manufacturing issues. The advanced circular cylindrical catalyst
shape 780 has a preferred diameter to height ratio in the range of
0.5:1 to 2.0:1, and more preferably in the range of about 0.5:1 and
1.0:1.0.
[0106] FIG. 12 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 780c with four internal generally L-shaped holes 800
(i.e., 800a, 800b, 800c and 800d). The hatched area 620c indicates
potential selections of the cylindrical ring catalyst 780c with a
diameter to height ratio in the range between about 0.5:1 to
1.0:1.0. The high performance catalyst particle 780c has a higher
Relative Particle Size Parameter (RPSP) and a Geometric Surface
Area (GSA) for a particular RPSP than a prior art catalyst
particle.
EXAMPLE 4
[0107] FIG. 13A shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings 880, and more
particularly cylindrical catalyst rings 880a, 880b, and 880c
according to the present invention. The catalyst 880 may optionally
defined curved or domed opposite ends 885a and 885b. The ends 885a
and 885b may be spherical, ellipsoidal or another curved shape, or
may be flat and circular.
[0108] Still referring to FIG. 13A, the rings 880a, 880b, and 880c
define at least one internal generally rounded-diamond-shaped hole
900. For example, the axial rounded-diamond-holed cylindrical ring
880b defines five generally rounded-diamond-shaped holes 900a,
900b, 900c, 900d and 900e. It is preferred that the axial
rounded-diamond-holed cylindrical ring 880 defines at least three
rounded-diamond-shaped holes 900.
[0109] FIG. 13B shows a top view of an axial rounded-diamond-hole
900. The axial rounded-diamond-hole 900 defines end curves 64' and
64A', having widths 65' and 66', and curved sides 67', 67A', 68'
and 68A'. Widths 65' and 66' are generally, but not necessarily of
equal length. Curved sides 67' and 67A' and end curves 64' and 64A'
may be circular or other curved shapes. Lengths 65' and 66'
generally may be, but are not necessarily equal.
[0110] Still referring to FIG. 13B, the rounded diamond-shaped hole
characteristic dimensions 65', 66', and the length of curved sides
67', 67A', 68' and 68A' may be so altered as desired along with the
number of holes 900 to obtain an optimal hole pattern within the
interior of the catalyst shape 880 to achieve desired catalyst
performance. The orientation of the Rounded Diamond-shaped holes
900 arrangement may vary, being parallel or perpendicular to the
radius from the central axis of the ring to the outer diameter or
in other arrangements, depending on the number of Rounded
Diamond-shaped holes 900 selected, and catalyst strength or
manufacturing issues. The advanced circular cylindrical catalyst
shape 880 has a preferred diameter to height ratio in the range of
0.5:1 to 2.0:1, and more preferably in the range of about 0.5:1 and
1.0:1.0.
[0111] FIG. 14 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 880b having five internal generally rounded-diamond-shaped
holes 900a, 900b, 900c, 900d and 900e. The hatched area 620d
indicates potential selections of the cylindrical ring catalyst
880b with a diameter to height ratio in the range between about
0.5:1 to 1.0:1.0. The high performance catalyst particle 880b has a
higher Relative Particle Size Parameter (RPSP) and a Geometric
Surface Area (GSA) for a particular RPSP than a prior art catalyst
particle.
EXAMPLE 5
[0112] FIG. 15 shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings 980, and more
specifically cylindrical catalyst rings 980a, 980b, and 980c
according to the present invention. The cylindrical catalyst 980
may optionally defined curved or domed opposite ends 985a and 985b.
The ends 985a and 985b may be spherical, ellipsoidal or another
curved shape, or may be flat and circular. The cylindrical catalyst
rings 980a, 980b, and 980c define at least one generally
diamond-shaped hole 1000. For example, the axial diamond-holed
cylindrical ring 980b defines five generally rounded-diamond-shaped
holes 1000a, 1000b, 1000c, 1000d and 1000e. It is preferred that
the axial diamond-holed cylindrical ring 980 defines at least three
diamond-shaped holes 1000.
[0113] Still referring to FIG. 15, the Diamond-shaped hole
characteristic dimensions "d" and "D2" may be so altered as desired
along with the number of holes 1000 to obtain an optimal hole
pattern within the interior of the catalyst shape 980 to achieve
desired catalyst performance. The orientation of the Diamond-shaped
holes 1000 arrangement may vary, being parallel or perpendicular to
the radius from the central axis of the ring to the outer diameter
or in other arrangements, depending on the number of Diamond-shaped
holes 1000 selected, and catalyst strength or manufacturing issues.
The advanced circular cylindrical catalyst shape 980 has a
preferred diameter to height ratio in the range of 0.5:1 to 2.0:1,
and more preferably in the range of about 0.5:1 and 1.0:1.0.
[0114] FIG. 16 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 980b with five internal generally rounded-diamond-shaped
holes 1000a, 1000b, 1000c, 1000d and 1000e. The hatched area 620e
indicates potential selections of the cylindrical ring catalyst
980b with a diameter to height ratio in the range between about
0.5:1 to 1.0:1.0. The high performance catalyst particle 980b has a
higher Relative Particle Size Parameter (RPSP) and a Geometric
Surface Area (GSA) for a particular RPSP than a prior art catalyst
particle.
EXAMPLE 6
[0115] FIG. 17A shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings 1080, and more
specifically cylindrical catalyst rings 1080a, 1080b, and 1080c
according to the present invention. The cylindrical catalyst ring
1080 may optionally defined curved or domed opposite ends 1085a and
1085b. The ends 1085a and 1085b may be spherical, ellipsoidal or
another curved shape, or may be flat and circular. The cylindrical
rings 1080a, 1080b, and 1080c define at least one generally
slot-shaped hole 1100. For example, the axial slot-holed
cylindrical ring 1080c defines six generally slot-shaped holes
1100a, 1100b, 1100c, 1100d, 1100e and 1100f. It is preferred that
the axial slot-holed cylindrical ring 1080 defines at least three
generally slot-shaped holes 1100.
[0116] The slot shaped holes 1100 define straight sides 103' and
104' and curved ends 105' and 106', which may be semi-circular or
another curved shape. Straight sides 103' and 104' can be
substantially equal length. Characteristic widths of slot shaped
holes 1100 are shown as 107' and 108'. However, the overall shape
of the slot shaped holes 1100 can vary without detracting from the
spirit of the present invention. For example, FIG. 17B shows an
asymmetric slot shaped hole 1100' with sides 103' and 104' that are
unequal in length, and curved ends 105' and 106' that are
non-circular in overall shape.
[0117] Still referring to FIG. 17B, the Slot-shaped hole
characteristic dimensions of straight sides 103 and 104 and curved
ends 105 and 106 may be so altered as desired along with the number
of holes 1100 to obtain an optimal hole pattern within the interior
of the catalyst shape 1080 to achieve desired catalyst performance.
The orientation of the slot-shaped holes 1100 arrangement may vary,
being parallel or perpendicular to the radius from the central axis
of the ring to the outer diameter or in other arrangements,
depending on the number of slot-shaped holes 1100 selected, and
catalyst strength or manufacturing issues. The advanced circular
cylindrical catalyst shape 1080 has a preferred diameter to height
ratio in the range of 0.5:1 to 2.0:1, and more preferably in the
range of about 0.5:1 and 1.0:1.0.
[0118] FIG. 18 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 1080c with six internal generally slot-shaped holes 1100a,
1100b, 1100c, 1100d, 1000e and 1000f. The hatched area 620f
indicates potential selections of the cylindrical ring catalyst
1080b with a diameter to height ratio in the range between about
0.5:1 to 1.0:1.0. The high performance catalyst particle 1080c has
a higher Relative Particle Size Parameter (RPSP) and a Geometric
Surface Area (GSA) for a particular RPSP than a prior art catalyst
particle.
EXAMPLE 7
[0119] FIG. 19 shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings 1180 rings, and more
specifically cylindrical catalyst rings 1180a, 1180b, and 1180c
according to the present invention. The cylindrical catalyst ring
1180 may optionally defined curved or domed opposite ends 1185a and
1185b. More specifically, the ends 1185a and 1185b may be
spherical, ellipsoidal or another curved shape, or may be flat and
circular.
[0120] The rings 1180a, 1180b, and 1180c define at least one
internal generally pear-shaped axial hole 1200 and at least one
external slot hole 1220. For example, the cylindrical ring 1180c
defines four internal generally pear-shaped axial holes 1200a,
1200b, 1200c, and 1200d, and four external slot holes 1220a 1220b,
1220c, and 1220d. The dimensions of the at least one pear-shaped
axial hole 1200 are as described with respect to FIG. 7. It is
preferred that the cylindrical ring 1180 defines at least three
pear-shaped internal holes 1200 and at least three external slot
holes 1220.
[0121] Still referring to FIG. 19, the pear-shaped and slot-shaped
hole characteristic dimensions "d", "W", "D2","D","t1" and "t2" may
be so altered as desired along with the number of holes 1200 to
obtain an optimal hole pattern within the interior of the catalyst
shape 1180 to achieve desired catalyst performance. The orientation
of the pear-shaped holes 1200 arrangement may vary, being parallel
or perpendicular to the radius from the central axis of the ring to
the outer diameter or in other arrangements, depending on the
number of pear-shaped holes 1200 selected, and catalyst strength or
manufacturing issues. The advanced circular cylindrical catalyst
shape 1180 has a preferred diameter to height ratio in the range of
0.5:1 to 2.0:1, and more preferably in the range of about 0.5:1 and
1.0:1.0.
[0122] FIG. 20 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 1180c with four internal generally pear-shaped axial holes
1200a, 1200b, 1200c, and 1200d, and four external slot holes 1220a
1220b, 1220c, and 1220d. The hatched area 620g indicates potential
selections of the cylindrical ring catalyst 1180c with a diameter
to height ratio in the range between about 0.5:1 to 1.0:1.0. The
high performance catalyst particle 1180c has a higher Relative
Particle Size Parameter (RPSP) and a Geometric Surface Area (GSA)
for a particular RPSP than a prior art catalyst particle.
EXAMPLE 8
[0123] FIG. 21A shows separate perspective, top and bottom, and
elevation views of cylindrical catalyst rings, and more
specifically cylindrical catalyst rings 1280a, 1280b, and 1280c
according to the present invention. The cylindrical catalyst ring
1280 may optionally defined curved or domed opposite ends 1285a and
1285b. More specifically, the ends 1285a and 1285b may be
spherical, ellipsoidal or another curved shape, or may be flat and
circular.
[0124] The rings 1280a, 1280b, and 1280c define at least one
internal generally teardrop-shaped hole 1300. For example, the
axial teardrop-shaped-holed cylindrical ring 1280c defines six
generally teardrop-shaped holes 1300a, 1300b, 1300c, 1300d, 1300e
and 1300f. It is preferred that the axial teardrop-shaped-holed
cylindrical ring 1280 defines at least three generally
teardrop-shaped holes 1300.
[0125] FIG. 21B shows a further top (or bottom) view of the
catalyst shape 1280 having axial teardrop holes 1300. Each teardrop
hole 1300 defines a curved end 144' with characteristic width 143,
opposite converging straight sides 145a' and 145b', and an outer
diameter 149'. The curved end 144' may be semi-circular or smaller
portions of a circle, less than semi-circular, or instead may be
formed as other curved shapes, including elliptical and fall within
the scope of this invention.
[0126] Still referring to FIG. 21B, the teardrop-shaped hole
characteristic dimensions of curved end 144' and straight sides
145a' and 145b' may be so altered as desired along with the number
of holes 1300 to obtain an optimal hole pattern within the interior
of the catalyst shape 1280 to achieve desired catalyst performance.
The orientation of the teardrop-shaped holes 1300 arrangement may
vary, being parallel or perpendicular to the radius from the
central axis of the ring to the outer diameter or in other
arrangements, depending on the number of teardrop-shaped holes 1300
selected, and catalyst strength or manufacturing issues. The
advanced circular cylindrical catalyst shape 1280 has a preferred
diameter to height ratio in the range of 0.5:1 to 2.0:1, and more
preferably in the range of about 0.5:1 and 1.0:1.0.
[0127] FIG. 22 shows a graph of GSA v. RPSP of the cylindrical ring
catalyst 1280c with six generally teardrop-shaped holes 1300a,
1300b, 1300c, 1300d, 1300e and 1300f. The hatched area 620h
indicates potential selections of the cylindrical ring catalyst
1280c with a diameter to height ratio in the range between about
0.5:1 to 2.0:1, and more particularly in the range between about
0.5:1 to 1.0:1.0. The high performance catalyst particle 1280c has
a higher Relative Particle Size Parameter (RPSP) and a Geometric
Surface Area (GSA) for a particular RPSP than a prior art catalyst
particle.
[0128] The advanced catalyst shapes disclosed in Examples 1 through
to Example 8 defines at least one axial hole with circular curves
combined with straight edges to form closed elongated curved shapes
which possess greater hole peripheral circumference than holes of
circular or regular-polygon shapes of the prior art. In addition,
the catalyst shapes of the present invention have equal or lesser
hole cross sectional area than holes of circular or regular-polygon
shapes of the prior art. The catalyst shapes of the present
invention have a greater geometric surface area per catalyst unit
volume than the prior art.
[0129] It should be noted that the above eight examples are
non-limiting examples and should not be viewed as limiting the
scope of the present invention. In addition, the invention includes
other permutations that might be found in U.S. Provisional Patent
Application Serial No. 60/402,580, filed Aug. 12, 2002. U.S.
Provisional Patent Application Serial No. 60/402,580 is
incorporated herein by reference in its entirety.
[0130] FIGS. 23 through to FIG. 30 compare the predicted catalytic
performance of a range of cylindrical catalyst particles of the
present invention with a variety of prior art catalyst particles.
The presented data demonstrates the improved catalytic activity of
the cylindrical catalyst particle of the present invention over the
prior art.
[0131] With respect to the chemical constituents of the cylindrical
catalysts of the present invention, non-limiting examples of
compositions are shown in Tables 1 and 2. Generally, nickel is
preferred as a cost-effective active catalytic constituent for
promoting the Hydrocarbon Reforming reactions. However, other
suitable catalytic constituents, which can be used alone or in
combination, include: Cobalt, Lanthanum, Platinum, Palladium,
Iridium, Rhodium, Rhenium, Ruthenium, Tin, Lead, Antimony, Bismuth,
Germanium, Arsenic, Cerium, Cesium, Yttrium, Molybdenum, Copper,
Zinc, Manganese, Chromium, Calcium, Titanium, Iron, Zirconium,
Magnesium, Phosphorus, and Potassium.
[0132] For Heavy Hydrocarbon Reforming applications, promoters can
be incorporated in the catalyst composition, including Potash or
other Alkali-Compounds and Zirconium or Magnesium oxides to further
improve catalyst activity. The active catalyst constituents are
combined on and within various support substances, especially
including Alumina, alpha-Alumina, Calcium-Aluminate,
Magnesia-Alumina, Zirconia, Spinel, Thoria, Titania, Silica,
Beryllia, Potash and other Alkali-earth compounds.
[0133] It should be understood that the cylindrical catalysts of
the present invention are suitable for promoting chemical reactions
other than Hydrocarbon Reforming reactions. For example,
cylindrical catalysts of the present invention are suitable for
aiding chemical reactions that are governed by the controlling
steps of diffusion through gaseous film and/or
absorbtion-desorbtion from active catalytic reaction sites.
[0134] It is to be understood that the present invention is not
limited to the embodiments described above, but encompasses any and
all embodiments within the scope of the following claims.
1TABLE 1 Chemical Compositions for the Cylindrical Catalysts of the
Present Invention Composition 1 Composition 2 Ni 0-25 Wt % 0-20 Wt
% SiO.sub.2 0-0.2 Wt % 0-0.2 Wt % Al.sub.2O.sub.3 Balance Balance
Composition 3 Composition 4 Ni 0-10 Wt % 0-25 Wt % SiO.sub.2 0.2 Wt
% 0-0.2 Wt % K.sub.2O 0-2 Wt % Al.sub.2O.sub.3 Balance Balance
Composition 5 Composition 6 NiO 0-20 Wt % 0-10 Wt % LaO 0-5 Wt %
0-5 Wt % SiO.sub.2 0-0.1 Wt % 0-0.1 Wt % Al.sub.2O.sub.3 Balance
Balance Composition 7 Composition 8 NiO 0-20 Wt % 0-20 Wt %
SiO.sub.2 0-0.1 Wt % 0-0.1 Wt % Al.sub.2O.sub.3 Balance -- K.sub.2O
-- 0-2 Wt % CaO/Al.sub.2 O.sub.3 -- Balance Composition 9
Composition 10 NiO 0-20 Wt % 0-10 SiO.sub.2 0-0.2 Wt % 0-0.1 Wt %
Na -- 0-0.1 Wt % K.sub.2O 0-2 Wt % 0-0.1 Wt % Mg Al.sub.2O.sub.4
Balance Balance
[0135]
2TABLE 2 Chemical Compositions for the Cylindrical Catalysts of the
Present Invention Composition 11 Composition 12 Composition 13 Ni
0-20 Wt % 0-20 Wt % 0-10 Wt % SiO2 -- 0-0.05 Wt % 0-0.05 Wt % C
0-0.1 Wt % 0-0.1 Wt % -- Na -- 0-0.15 Wt % -- S -- 0-0.05 Wt %
0-0.05 Wt % Cl -- 0-0.02 Wt % 0-0.02 Wt % Al.sub.2 O.sub.3 Balance
Balance Balance K.sub.2O 0-2 Wt % -- -- CaO 0-15 Wt % -- --
* * * * *